Although over 160 foods can cause allergic reactions, the Centers for Disease Control and Prevention list just eight foods that cause 90 percent of these reactions: wheat, soybeans, fish, shellfish, eggs, cow’s milk, peanuts and tree nuts. These foods are collectively called the Big-8.

Over the next week, we’re diving deeper into the Big-8 food allergies, breaking down each one with tips, specifics, alternatives, the latest research, and online or mobile resources. Read on for our quick guide to the top 8 food allergies.

Food Allergy Statistics: The Big Picture

Food allergies affect 4 percent of adults and just under 5 percent of children under the age of 5, according to the latest statistics from the National Institutes of Health. In October 2008, the National Center for Health Statistics released adata brief on food allergies in U.S. children; the following tables are from that brief.

Here’s the NCHS 2007 breakdown by gender, ethnicity group and age range for children with food allergies:

Reported food allergy cases rose 18 percent in children under the age of 18 between 1997 and 2007 — that’s an estimated 3 million affected children.

Kids with food allergies are also far more likely to have respiratory or skin allergies than their classmates without food allergies.

Today’s kids are also more likely to be hospitalized due to a food allergy than in prior years.

A closer look into the Big-8 food allergies reveals some compelling statistics. Read on for a snapshot of the top 8 food allergies.

Cow’s Milk Allergy

(CC) www.bluewaikiki.com/Flickr

An allergy to cow’s milk isn’t the same as lactose intolerance. Those who are lactose intolerant have a deficiency in the lactase enzyme, which breaks down lactose into sugar; these individuals can typically tolerate some lactose in their diet, but they can’t digest it fully, according to the National Digestive Diseases Information Clearinghouse. Those with a milk allergy, on the other hand, can experience severe, even life-threatening reactions after consuming just a sip or two of milk.

Food Allergy vs.
Food Intolerance

Food allergy and food intolerance are two different reactions to specific foods that are often confused. Food allergies provoke the immune system to react to trigger foods it identifies as harmful; allergy symptoms can be life-threatening. Food intolerance provokes the digestive system; its symptoms are uncomfortable, but not life-threatening, and include diarrhea, bloating and stomach cramps.

Sample foods that could trigger allergy symptoms (1):

Butter

Cheese

Cottage cheese

Pudding or custard

Ice cream, sherbet

Milk, cream and half-and-half, including sheep and goat milk

Yogurt

Deli meat, lunch meat, sausages or hot dogs

Margarine

Sour cream

Statistics (1, 2):

Milk is the most common food allergy in early childhood.

In their first year of life, 2 to 3 percent of babies in developed countries will have a milk allergy.

45 to 50 percent of babies grow out of their milk allergy by their first birthday.

60 to 75 percent of toddlers will grow out of their milk allergy by the age of 2.

85 to 90 percent of toddlers will grow out of their milk allergy by the age of 3.

On average, the remission rate of a milk allergy in infancy is 85 to 90 percent.

50 percent of babies who have a milk allergy will develop allergies to other foods before puberty.

50 to 80 percent of babies who have a milk allergy will become allergic to inhalants such as pollen, dander or dust mites before puberty.

Egg Allergy

(CC) John Morgan/Flickr

Egg allergies cause an abnormal reaction in affected individuals’ immune systems when they consume egg proteins in any form. Egg allergies primarily occur in children, but most kids will outgrow the allergy by the time they reach adulthood. Those with an egg allergy should consult their doctor before receiving some vaccines, as these immunizations may contain egg protein; we’ll dive deeper into specific shots in a later post.

Sample foods that could trigger allergy symptoms (1):

Ice cream

Cake, muffins, cream pies, cream puffs and souffles

Frosting, custard, marshmallows and meringue

Battered fish, meat or poultry

Hollandaise sauce, tartar sauce or mayonnaise

Some egg substitutes

Waffles

Eggnog

Creamed soups or prepared foods

Pudding

Statistics (1):

Egg is the second most common food allergy in early childhood.

1.5 to 3.2 percent of children under 3 have an egg allergy.

By age 4, 4 percent of children will outgrow their egg allergy.

By age 6, 12 percent of children will outgrow their egg allergy.

By age 10, 37 percent of children will outgrow their egg allergy.

By age 16, 68 percent of children will outgrow their egg allergy.

Children who are severely allergic to eggs can remain allergic through adulthood.

In a 2007 study of 881 patients with egg allergies, 75 percent were also allergic to peanuts.

Asthmatic children with an egg allergy will take longer to develop tolerance to eggs — about 5 more years — than kids with an egg allergy who do not have asthma.

Children with an egg allergy and other food allergies will take longer to develop tolerance to eggs than kids who are only allergic to eggs.

Peanut Allergy

(CC) Martin L/Flickr

Exposure to even a trace amount of peanuts can trigger peanut allergy symptoms, which range from mild but uncomfortable to severe and life-threatening. Peanut allergy is the deadliest of the food allergies in that it is the top cause for food-allergy-related anaphylaxis deaths.

Sample foods that could trigger allergy symptoms (1, 2):

Peanuts, peanut oil

Peanut butter

Thai, African, Chinese and other ethnic cuisine

Baked goods such as biscuits, cookies, bread and crackers

Ice cream

Sauces

Energy bars, candy

Soup

Natural flavoring

Nougat

Statistics (1, 2, 3, 4):

1.4 percent of children have a peanut allergy, according to a 2008 study (3). This is up from 0.4 percent in 1997.

2 percent of the population has an allergy to peanuts.

20 percent of children with a peanut allergy will outgrow it.

The number of children with peanut allergies doubled between 1997 and 2002 and tripled between 1997 and 2008.

95 percent of people with a peanut allergy can eat soybeans or beans without experiencing allergy symptoms.

20 percent of allergic reactions to peanuts and tree nuts result in anaphylaxis.

Peanut allergy is the top cause for fatal food anaphylaxis.

Over 3 million U.S. residents have peanut allergies, tree nut allergies or both.

Despite strict vigilance, the average person with a peanut allergy will be exposed to peanuts once every three to five years from an unusual or unexpected source.

40 percent of individuals with a fish allergy experienced their first allergic reaction as an adult.

2.3 percent of U.S. residents have a seafood allergy.

Over 50 percent of people are allergic to more than one type of fish.

The primary allergen in fish is parvalbumin.

40 percent of individuals discover their fish allergy in adulthood, a 2004 survey found (4).

Shellfish Allergy

(CC) Hellen Stevens/Flickr

Shellfish allergy symptoms are most often triggered by lobster, shrimp and crab. Unlike some of the other food allergies in the Big-8, shellfish allergy typically develops in adulthood or late childhood. Some people are allergic to fish, but not shellfish. Similarly, someone may be allergic to shellfish, but not crustaceans. Those with severe shellfish allergies can experience an allergic reaction from simply handling shellfish or inhaling airborne shellfish proteins in a kitchen setting.

Sample foods that could trigger allergy symptoms (1):

Crustaceans, such as shrimp, crab, lobster and crawfish

Abalone, clams, mussels, sea urchins

Squid

Snails or escargot

Octopus

Oysters

Cockles

Fish stock

Seafood flavoring

Bouillabaisse

Statistics (1, 2, 3, 4, 5):

7 million Americans report that they have a seafood allergy, making it the most common Big-8 food allergy in adults.

Unlike those who have other food allergies, those with a shellfish allergy typically do not grow out of it.

The primary allergen in shellfish is invertebrate tropomyosin, a protein that also occurs in mollusks, insects and even cockroaches.

60 percent of individuals discover their shellfish allergy in adulthood, a 2004 survey found (4).

Shellfish allergies are significantly more prevalent in areas where shellfish is a dietary staple, such as Singapore and Thailand.

10 percent of food-induced anaphylaxis cases in France are caused by crustaceans.

Soy Allergy

(CC) Kanko/Flickr

Soy allergies typically appear during childhood, but adult soy allergies are also possible. Soy appears throughout processed food, which makes it quite difficult to avoid in a standard American diet. Those with a moderate to severe soy allergy may also experience allergic reactions after consuming other legumes, such as peanuts, beans, licorice and lentils.

Wheat Allergy

(CC) mr.bologna/Flickr

Those with a wheat allergy are sensitive to albumin and globulin, two proteins in wheat. This allergy is slightly different from celiac disease, whose sufferers are sensitive to gluten proteins. See the sidebar to the right for more differences between wheat allergy and celiac disease — two conditions that are often confused. Allergic reactions can occur after consumption of wheat, while exercising after consumption of wheat or after accidentally inhaling flour — for example, in a bakery or home kitchen.

Celiac Disease vs. Wheat Allergy

Celiac disease and wheat allergies share wheat as a culprit, but the two conditionsdiffer considerably. Celiac disease is a genetic autoimmune disease; it causes the body to produce antibodies that attack the villi in the small intestine when the affected individual consumes gluten. People with a wheat allergy can grow out of their allergy; people with celiac disease have the condition for life.

Sample foods that could trigger allergy symptoms (1):

Bread, bread crumbs

Flour, high-protein flour, enriched flour

Couscous, pasta

Semolina wheat

Soy sauce

Cereal extract, bran, wheat germ

Vegetable gum

Starch, cracker meal

“Natural” flavoring

Bulgur, durum, farina

Statistics (1, 2, 3):

0.4 percent of children have a wheat allergy.

29 percent of wheat-allergic children will grow out of it by age 4.

56 percent of wheat-allergic children will grow out of it by age 8.

65 percent of wheat-allergic children will grow out of it by age 12.

70 percent of wheat-allergic children will grow out of it by age 14.

35 percent of wheat-allergic children will continue to carry their allergy into their teens.

20 percent of children who have a wheat allergy also have allergies to other grains.

Symptoms and Diagnosis

The best way to diagnose a food allergy is to head to a physician or an allergist for a professional opinion. The doctor or allergist will typically perform one of four examinations to test for a food allergy: a skin test, a blood test called the radioallergosorbent test (RAST), an oral challenge in which the patient eats a suspected food, and an elimination diet, in which the patient avoids eating the suspected food for 10 to 14 days.

Specific symptoms of an allergic reaction vary between individuals depending on the severity of their food allergy. However, allergic reactions typically fall into two categories: the digestive tract and body systems.